INTRODUCTION: This study aims to characterize the cellular components of major salivary gland tumors and to identify the differentiating markers between tumor subtypes.
METHODS: Between January 2006 and December 2010, a total of 83 patients (42 males, 41 females; mean age 50.2±15.8 years; range, 21 to 82 years) with major salivary gland tumors (n=12 mucoepidermoid carcinomas, n=8 adenoid cystic carcinomas, n=3 acinic cell carcinomas, n=4 salivary duct carcinomas, n=2 myoepitheliomas, n=5 basal cell adenomas, n=31 pleomorphic adenomas, and n=18 Warthin tumors) with myoepithelial and epithelial immunohistochemical markers (smooth muscle actin [SMA], calponin, S100, CD10, GFAP, p63, GCDFP15, GLUT1, 34ßE12, CK14, CK19, CD117, and galectin-3) were evaluated using tissue microarray method.
RESULTS: The GFAP, S100, CK14, p63, and CK5/6 expressions were significantly lower in the malignant tumors (p<0.05), whereas the expression of neither SMA, nor calponin was significantly different between benign and malignant tumors. The CK19 expression was significantly higher in malignant tumors (p=0.004). Diffuse CD117 expression favored an adenoid cystic carcinoma; GFAP expression favored a pleomorphic adenoma; 34ßE12, p63, and CK5/6 expression favored a mucoepidermoid carcinoma; and GCDFP15 favored a salivary duct carcinoma and acinic cell carcinoma.
DISCUSSION AND CONCLUSION: Our study results showed that distinct tumor types exhibited different preferences for various markers. We, therefore, suggest that immunohistochemical characteristics of myoepithelial cells, rather than the quantity per se, show a significant difference between malignant and benign salivary gland tumors and CK19 expression may indicate the malignant nature of a salivary gland tumor in difficult-to-diagnose tumors.